Ethernet (registered trademark) is mainly used as a communication method between servers in a data center. In general, the amount of data communicated between servers in a data center is large, and there is a problem of increasing the cost of the installation of facilities such as network switches, cables, and Ethernet cards for communication via Ethernet.
Further, a PCIe switch is used as a communication tool between a high-speed server and a device connected to the server. For example, Patent Literature 1 discloses a computer system where multiple computers and multiple input/output devices are connected by a PCIe switch. Patent Literature 2 discloses a technology for sharing an I/O device by allocating multiple virtual functions (VF) of a PCI device to multiple blades by use of a PCIe switch. Further, Patent Literature 3 discloses a technology for detecting a path error in a communication system where servers are connected by a layer 2 switch.